In May this year, a fire at the Gateway energy storage power station in San Diego County, California, the "world's largest battery energy storage project", once again pushed the safety of energy storage systems to the peak of public opinion. The power station was connected to the grid in August 2020 and suffered a catastrophe after just over three years of operation.
The safety of energy storage system has become a must for the whole industry. Especially in the Chinese market, the soaring energy storage industry, due to the uneven quality of participants, driven by the competition for distribution and storage policy dividends, has fallen into the unhealthy competition of low-price competition at this stage, and has exposed multiple problems under the current situation of imperfect industry standards. Wu Jiaxiang, senior vice president of Sungrow, pointed out in a public speech in April this year that "the energy storage industry is entering a period of rapid development, but there are still hidden concerns in terms of investment, operation and safety of energy storage projects." ”
As the "eight-year champion" of global market shipments among Chinese enterprises, Sungrow has continued to "break the problem" for the industry in recent years around energy storage safety.
During the annual Shanghai SNEC exhibition, Sungrow released the "ArcDefender™ Energy Storage DC Arc Pulling Technology White Paper", which filled the technical gap in the industry in energy storage arc pulling technology, and also announced the successful completion of the world's first large-scale combustion test demonstration of energy storage system, showing the industry what is called "real machine is not afraid of fire refining" and what is energy storage safety with the courage of industry leaders.
Combustion test evidence, for quality endorsement
Fire risk is a pain point in electrochemical energy storage. According to authoritative statistics in the industry, in the seven years from 2017 to 2023, there have been about 100 energy storage accidents around the world, including about 59 fire accidents.
At this year's SNEC 2024, Sungrow announced that it had successfully completed the world's first large-scale combustion test demonstration of energy storage system, and obtained the test report from DNV, an international authoritative certification body. This is the first time in the world to use a large-capacity energy storage real machine to simulate the real scene layout.
This combustion test was composed of 4 PowerTitan real machines of Sungrow, and the construction of a real power station was simulated. Witnessed by many customers around the world, Sungrow took the initiative to detonate a real PowerTitan energy storage system, and after 4 hours of burning without the fire spreading, the energy storage cabinet was still able to maintain its structural integrity.
The core guarantee of this PowerTitan can withstand the "fire refining", and it is a multi-layer advanced design such as air pressure sensing explosion venting, multi-layer fire resistance and double compartment structure.
Behind the real machine, where does Sungrow's courage to take the lead in "solving problems" for the industry come from?
Li Guohong, general manager of Sungrow's energy storage division, said in an interview that solid research and development has supported the hard power of Sungrow's energy storage products.
First of all, Sungrow has a "first-mover advantage" in the field of energy storage system integration, and has accumulated a large number of application cases in the power supply, power grid and user side. Secondly, the energy storage business has a professional R&D team, from cell research, material research, software research to system research department, all of which are simultaneously carrying out large-scale R&D testing, simulation and calculation work, which is the "key element" for the continuous upgrading of solar energy storage system products; Thirdly, Sungrow attaches great importance to "going to the client and going to the field", and feeds back the latest needs of customers in the application scenario and the design redundancy of the site to the product planning end of the energy storage system, and iterates the closed loop in the development of the next generation of new products.
Regarding how to define "good products" in Sungrow, Li Guohong believes that "products that are responsible for quality and reliability are good products, and truly high-quality energy storage system products are responsible for the client's income for 10 or 20 years." ”
Breakthrough in DC arc pulling technology, "solving problems" for the industry
In order to pursue more significant cost reduction and efficiency increase, the single capacity of energy storage cells is increasing at an astonishing speed, and the energy storage system is also evolving to high-voltage and high-current technologies. With the maturity of high-voltage technology, 1500V energy storage system has become the mainstream; At the PAT conference in March this year, Sungrow released the latest photovoltaic energy storage 2000V high-voltage technology achievements, raising the voltage and current level to a new height.
"With the application of large-capacity and long-term energy storage, the current and voltage levels on the DC side continue to rise, which puts forward higher requirements for the safety of the system. Among the various factors that cause power station fires, DC arc pull fault is the main cause of fire accidents. Li Guohong said at the 2024 SNEC exhibition.
This is also the significance of Sungrow's joint Jianheng joint release of the "ArcDefender™ Energy Storage DC Arc Pulling Technology White Paper".
The so-called "arc pulling" is a continuous discharge phenomenon that occurs when the live conductor (energy storage) is close to the conductor, and the voltage between the conductors breaks down the gas and ionizes the gas. In both AC and DC systems, arcing phenomena occur, where DC arcing causes more persistent accidents and higher fire risks due to stable current and strength.
On the DC side of energy storage, due to the complexity of system control logic and the bottleneck of data transmission efficiency, DC arc detection and shutdown technology are still blank in China.
However, the hazards of arcing risk have to be taken seriously. According to Li Guohong, "on the DC side of energy storage, the connection point of power electronic equipment (compared to the AC side) is exponentially higher, and once the arcing phenomenon occurs, the energy released is much higher than that of the photovoltaic power station, and the risk of fire is higher." ”
Image source: ArcDefender™ Energy Storage DC Arc Pulling Technology White Paper
With tens of thousands of electrical connections on the DC side of the energy storage system, the risk is hidden. According to the white paper, taking the 5MWh energy storage system as an example, there are about 11,016 connection points on the DC side (918 connection points for each battery cluster), while there are only 216 connection points on the AC side, and the number of electrical connection points on the DC side is more than 50 times that of the AC side, and the risk is dozens of times higher than that on the AC side.
In view of the safety challenges of arc pulling of energy storage systems, Sungrow has built a technical platform integrating arc risk prediction, sensing and suppression, and created the PCS arc recognition dynamic algorithm, as well as core technologies such as high-precision sensing and risk data monitoring, which can realize arc prevention, accurate arc recognition and rapid arc extinguishing at the source.
According to the test and verification results, Sunshine's technical performance using ArcDefender™ has reached the "Level 4" level in CGC/GF 240:2024 "Technical Specification for DC Arc Detection and Breaking Evaluation of Energy Storage Systems" - L4 means the highest level of this safety standard.
More importantly, the white paper also released the testing specifications at the same time, and disclosed the relevant standards to the industry. "At the moment of rapid growth of the industry, we must recognize and pay attention to potential risks, and also hope that through the disclosure of norms, we can achieve breakthroughs and leadership in industry standards. As a leading enterprise, Sungrow has the responsibility to promote the healthy development of the industry, and it is also the embodiment of corporate social responsibility. Li Guohong said.
Promoting the "globalization" of energy storage safety standards
Energy storage safety is a system-level project, at present, there is a gap between the safety standards of the domestic market and the overseas market, and the existing safety system construction is far from catching up with the speed and scale of the energy storage market. In July, the implementation of the "new national standard" for electrochemical energy storage batteries is imminent, and the performance and safety indicators of electrochemical energy storage will be further improved.
Recently, some provinces and cities with rapid development of industrial and commercial energy storage in China have begun the "safety rectification storm", and launched stricter rectification measures for fire protection of energy storage power stations. According to industry insiders, taking some areas of Zhejiang Province as an example, the cost of fire rectification for a single energy storage power station may increase by up to 100,000 yuan, which is to push up the hidden non-technical cost of energy storage power stations.
With stricter safety regulations coming, how should energy storage manufacturers respond? Li Guohong believes that "the essence of solving the safety of energy storage systems is not in 'elimination', but in 'prevention'." Only through innovation in R&D can the system cost of the whole life cycle be truly reduced. Sungrow's system-level products have withstood the most stringent inspections in overseas markets, especially in the North American market, which has the highest safety standards. We will work with professional institutions to accelerate the construction of industry safety standards and realize the 'globalization' of energy storage safety standards." ”
Previously, on how to strengthen technological innovation, quality control and adhere to the bottom line of safety, Wu Jiaxiang of Sungrow has summarized the three major solutions that Sungrow adheres to, of which the soul law is one sentence - "let the installation return to the factory and leave safety on site." "Responsible energy storage manufacturers should complete a large number of product tests, safety tests, and grid-connected tests in the factory, rather than at the installation site.
It is reported that the PowerTian2.0 series of DC arcing technology with ArcDefender™ has recently been implemented and applied in industrial and commercial scenarios such as iron and steel enterprises, and has been successfully connected to the grid and has begun to accept the test of "two charging and two discharging", which fully verifies the grid-connected capability and system reliability of the AC storage solution.
With more than 10 years of experience in the overseas energy storage market, this energy storage giant has been keenly aware of industry trends and application risks for a long time. From the solution to the first DC parallel arc pulling fault of a photovoltaic power station, to the industry's first battery cell pre-diagnosis product iSolarBPS (previously reported "Dialogue with Sungrow Xu Sheng: Energy Storage is Still in the "Assembly" Era, Sungrow's iSolarBPS Solution Promotes the Evolution of Energy Storage Security), and then to the release of DC arc pulling technology for energy storage systems, Sungrow's technological breakthroughs and innovations in system safety are clearly visible. China's energy storage market is in need of such a "problem-solving champion" who attaches importance to energy storage safety.
(Please indicate the source for reprinting, article source: Huaxia Energy Network, WeChat ID: hxny3060)